stelio montebugnoli ira -inaf- bologna –italy-

S.MontebugnoliBEST4th SKADS Workshop, Lisbon, 2-3 October 2008

Stelio Montebugnoli IRA -INAF- Bologna –Italy-

SKADS 4th -Lisbon- Oct 2-3, 2008


DS-6DS-6

110

mt

E/W

N/S

24

mt4 receivers

F=408 MHz @ 16 MHz

BEST-1: 170 sqm 4 Rx BEST-2 : 1400 sqm 32 RxBEST-3: 3200 sqm 60 Rx (14 cylinders +1 E/w 24 mt line) equivalent to a 64 mt diameter dish


(More details are reported in the J. Monari talk)

DS-6: Basic architecture & related blocksDS-6: Basic architecture & related blocks

optical fiber

F.E. Developed - Single end front end- Differential front end- Balanced front end

Main requirements:- Low cost- Low noise- Reliable- High dynamic range

IFA/D

&Data Proc.LO

distributor LO

OP.Rx

OP.Tx

F.E.

Synth.

Sync


Reliabilty prediction exercise for the front end

The analysis has been implemented by means of MIL-HDBK-217H reliability database

Hypothesis:• Reliability Block Diagram: series configuration• 100% Duty cycle• Operating Temperature: 40°C• Operating environment: MilStd Ground MobileMilStd Ground Mobile (Front-end) and MilStd Ground Fixed UncontrolledMilStd Ground Fixed Uncontrolled (Downconversion)

Reliability Data (MTBF) Front-end: 127365 hours 14.5 Years

RELIABILITY PREDICTIONRELIABILITY PREDICTION

By the evaluation of MTBF (Mean Time Between Failures) variations while stillBy the evaluation of MTBF (Mean Time Between Failures) variations while stillin the project design phase, it is possible to increase the system reliability.in the project design phase, it is possible to increase the system reliability.

Florence College of Engineering


OpticalTx

OpticalRx


optical fiberIF

A/D &

Data Proc.LO distributor LO

OP.Rx

OP.Tx

F.E.

Synth.

Sync


(More details are reported in the F. Perini talk)

Collaboration with ANDREW WIRELESS SYSTEMS and MITEQ on analogue optical links will last till the end of SKADS

• IRA is collaborating with :AWS on the test of a 4.5 GHZ Tx, equipped with a cooled

Laser. MITEQ to optimize a standard commercial products to satisfy

the requirements. A plan to design an ad hoc low cost optical link is considered as well.

… VCSEL represents the only way to reduce costs of the optical link. IRA plans for a prototype at the end of SKADS but it is not clear the role that ANDREW and MITEQ will play in this task.


optical fiberIF

A/D &

Data Proc.LO distributor LO

OP.Rx

OP.Tx

F.E.

Synth.

Sync


DS-6: DS-6: Basic architecture & related blocksBasic architecture & related blocks

Xmas tree OLdistribution

Div x 8

IFA/D

&Data Proc.LO

distributor LO

OP.Rx

OP.Tx

F.E.

Synth.

optical fiber

Sync


IFA/D

&Data Proc.LO

distributor LO

OP.Rx

OP.Tx

F.E.

Synth.

optical fiber

Sync


A/Filt.

A/D &

Data Proc.

OP.Rx

OP.Tx

F.E.

Synth.

optical fiber

Sync

RF Direct Digitization …potentially possible with the “Casper” system…BEST works at 408 MHz and the A/D can sample at more the 1 GS/s.



Input ofOptical fibre

IF

IFA/D

&Data Proc.LO

distributor LO

OP.Rx

OP.Tx

F.E.

Synth.

optical fiber

Sync



IFA/D

&Data Proc.LO

distributor LO

OP.Rx

OP.Tx

F.E.

.

optical fiber

Sync

Sync x 32 for A/Ds


Low Noise balanced Amplifier

IF Amplifier

Architecture and technology for immediate application onthe BEST - x demonstrator construction (T0+10mo).

Optical Fiber

To A/D & Signal Proc.

From Sensor



IFA/D

&Data Proc.LO

distributor LO

OP.Rx

OP.Tx

F.E.

.

optical fiber

Sync

For the A/Ds and post processing blocks, the Berkeley-CASPER Boards have been used….



Wide band A/D converter: dual 8 bits @ 1 GS/Sec converter (4 A/D for each IBOB packetizer board

Wide band A/D

FPGA

CASPER system :A/D+ IBOBs + Bee2 Our collaboration is starting with South Africa and Berkeley

A/D+ IBOB

A/D and data Processing



One Bee2 board can deliver 500 GOps/sec with a 400 W power supply.

• 6.7 MOps /€•1.25 GOps/W


Xilinx Virtex 2 Pro 70(100 as well)




A 32 receivers FX correlator (2048 ch)has been programmedin 1 week time in the frame of a colalboration starting from South Africa (Alan Langman, Jason Manley), IRA and Berkeley (D. Werthimer, Aaron Parsons).


∑FFTZ-n

FFTZ-n

FFTZ-n

∑

∑


Basic FX Correlator block diagram



Basic Modular FX Correlatorblock diagram


FX correlator with Bee-2FX correlator with Bee-2

- Complex multiply allows for fine delay control and per channel digital gain control- White coloured blocks not yet implemented




1-2 interferometer

CAS. A, 1 h of data

Rx1, Rx 2 baseline (outermost receivers). The fringes are clearly visible. However, the RFI are quite big.



1-2 interferometer

CAS. A, 1 h of data

…… with the RFI flagged. The fringes are now clean.


CAS. A, 1 h of data


CAS.A with strong RFIs (Tv station in the lower part of the band)

CAS. A, 1 h of data



CAS. A, 1 h of data

CAS.A with strong RFIs (the Tv station in the lower part of the band are mitigated)


DS-6: DS-6: T4 Phased array on concentrators T4 Phased array on concentrators

Focusing the task with J.G. B.de Vaate and Laurens Bakker

It could be feasible to install a tile on the focal line… …..but after an electromagnetic analysis


• A zoom shows the strong source in the center and the image artifacts. The deconvolution worked very well. Most of the source has been phased up into a single pixel at 50deg 48min 53.6s (CAS)


stelio montebugnoli ira -inaf- bologna –italy-

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